youtube/vitess — pull request #154 by enisoc (2014-11-12 07:10:08+00:00)
Title: Add tracing in rpcplus and other places downstream from tabletmanager.

@alainjobart @sougou

The goal is to start getting useful traces out of tabletmanager.
To start, we trace outgoing RPC calls on the client side.
Certain high-level TopoServer operations are also traced at this point.

To facilitate tracing, I've begun plumbing Context through tabletmanager
and all its users. At this time, it is simply a few regexes adding the
parameter so it can be used by tracing; no timeouts or cancellation are
using Context yet. Those use cases will require more careful
consideration.

Other than tabletmanager, most callers use context.TODO() since they
aren't plumbed yet.